1. Field of the Invention
The present invention relates to a method for operating a computed tomography device for reducing the load on at least one technical component of the computed tomography device during operation of the at least one technical component. The invention also relates to a non-transitory computer-readable data storage medium encoded with programming instructions for implementing such a method, and a computed tomography device operable according to the method.
2. Description of the Prior Art
A computed tomography device, in particular a third generation computed tomography device, embodies a number of technical components, which during operation of the computed tomography device are subject to a significant load and are therefore subject to age or wear. The ageing and wear are generally greater or more marked, the closer the respective technical component is operated to its load limit.
Such a technical component is, for example, an x-ray tube of a computed tomography device. The service life of an x-ray tube is influenced significantly by the strength of the tube currents used during operation of the x-ray tube. Major temperature fluctuations are a particular problem, resulting in particular from secondary electrons striking the beam outlet window of the x-ray tube. The temperature here rises in a linear manner with the tube current used. In particular x-ray tubes frequently operated close to or at their maximum permissible tube current therefore age more quickly and often have to be replaced prematurely, thereby incurring not insignificant costs.
Further technical components of the computed tomography device, which during operation at or close to their load limit are subject to increased wear, are bearings for the rotating support of the rotatable part relative to the stationary part of the gantry and slip rings for the transmission of data and/or energy between the rotatable and stationary parts of the gantry of the computed tomography device.
The reason why technical components are operated at their load or performance limit is frequently due to the operation of a computed tomography device that has technical components for cost reasons have a low reserve capacity, with automatic program systems, e.g. automatic dose systems, with which the tube current of the x-ray tube of the computed tomography device is modulated as a function of the rotation angle and therefore of the body cross section of a patient to be irradiated, in order to reduce the dose of x-ray radiation to be applied to a patient whilst still ensuring the best possible image quality. The tube current is reduced, for example for x-ray projections in an anterior-posterior direction, and is increased for x-ray projections in a lateral direction, where beam attenuation is greater. The automatic dose system therefore ensures that the patient is scanned with minimal exposure. In order also to be able to obtain high quality image information from an adipose patient, who generally demonstrates greater beam attenuation than a patient of normal weight, the automatic dose system must frequently increase the tube current so that the x-ray tube with low reserve capacity is operated close to or at its maximum permissible tube current, with the result that it is subject to a significant load and therefore premature ageing.